[CBRD-24387] Rewrite page handling for overflow oid in btree

[ctshim]

http://jira.cubrid.org/browse/CBRD-24387

• Perform unnecessary code cleanup and rewrite without changing functionality.

• The btree_rv_save_keyval_for_undo_two_objects() is called with BTREE_OVERFLOW_NODE only.
• Fix BTREE_INIT_MVCC_HEADER()
• Fix heap_attrinfo_generate_key()
  When func_index_info is set, information necessary for single key generation is read from this function.
• Change space_slot_size() and space_header_size() from a function to a macro.
• The following functions were subdivided.
  xbtree_load_index(), btree_construct_leafs(), online_index_builder(), xbtree_load_online_index()
• Remove scan_cache argument from heap_attrinfo_read_dbvalues()

[beyondykk9]

what does mean S_PARAM_ST? sort parameter structure?

[ctshim]

Temporary structures have been defined to reduce what will be passed to the parameters of the function.
There is no particular meaning to the name of the structure.

[youngjinj]

It is trivial.
Is it to reduce comparison in case of S_SUCCESS?

[ctshim]

Yes, to reduce comparisons of if statement.